Flexible Pipe Carcass Layer Using Interlocking Hoop Elements
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Solution Overview
Problem
Existing methods for forming a carcass layer in flexible pipes are time-consuming and costly, limit material choices, and restrict the use of different materials and shapes, compromising between malleability and strength, especially at extreme water depths where crushing forces are significant.
Innovation Solution
The use of independent hoop elements made from various materials, which can be manufactured separately and interlocked to form a carcass layer, allowing for different strengths and shapes along the pipe length, and the incorporation of aerogel materials for improved insulation and reduced thermal conductivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a profiled tape is used to form the carcass layer by helical winding, then the pipe can withstand crushing forces at depth, but the manufacturing process becomes time-consuming and costly
Solution Approach 1:
The carcass layer is segmented into discrete interlocking hoop elements rather than being formed by continuous helical winding of profiled tape. Each hoop element is manufactured separately and then assembled, eliminating the time-consuming profile rolling process and enabling parallel manufacturing of multiple hoops simultaneously.
Solution Approach 2:
The hoop elements are pre-manufactured with their interlocking features (protrusions and recesses) already formed, allowing them to be quickly assembled into the carcass layer. This preliminary formation of structural features eliminates the need for complex real-time profiling during the winding process.
2Ease of manufacture
If profiled tape is manufactured by rolling, then the carcass layer can be formed, but material choices and shape options are limited
Solution Approach 1:
By segmenting the carcass into discrete hoops, each hoop can be manufactured from different materials and with different cross-sectional shapes independently. This allows selection of optimal materials (such as high-strength alloys, composites, or polymers) and shapes (circular, oval, irregular) for specific depth requirements without being constrained by rolling process limitations.
Solution Approach 2:
The invention changes the manufacturing parameters from continuous profile rolling to discrete hoop fabrication, enabling a broader range of material properties and geometric parameters. Hoops can be produced with varying wall thicknesses, cross-sectional areas, and material compositions to optimize performance for different water depths and pressure conditions.
3Ease of manufacture
If continuous tape winding is used, then the carcass layer is formed, but material uniformity is required along the entire length
Solution Approach 1:
The carcass layer is divided into discrete hoop elements that can be manufactured from different materials or with different properties. This segmentation allows the pipe to have varying material characteristics along its length, such as using higher-strength materials in deep-water sections and lighter materials in shallow sections, optimizing both performance and cost.
Solution Approach 2:
Different hoop elements can be tailored with local quality variations, where each hoop's material composition, wall thickness, or cross-sectional shape is optimized for its specific position in the pipe assembly. This enables gradient structures where properties change progressively along the pipe length to match varying environmental conditions.
4Strength
If profiled tape is used for the carcass layer, then crushing resistance is provided, but the second moment of inertia is limited
Solution Approach 1:
The invention changes the geometric parameters of the carcass structure by using hoops with optimized cross-sectional shapes that can achieve higher second moments of inertia. By varying the hoop cross-section (such as using thicker walls, larger radii, or more complex profiles), the bending stiffness and crushing resistance can be significantly enhanced beyond what is achievable with standard profiled tape windings.
Data Source
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AI summary
Flexible pipe body for transporting fluids from a sub-sea location, including a carcass layer comprising a plurality of independent hoop elements each comprising a body portion having a circular outer surface that circles around an inner circumference of a bore region of the flexible pipe, said body portion being arranged to interlock adjacent hoop elements together. A method of manufacturing flexible pipe body is also enclosed.